1. Field
The present disclosure relates generally to landing gear and, in particular, to semi-levered landing gear. Still more particularly, the present disclosure relates to an air-ground detection system for semi-levered landing gear.
2. Background
Many airplanes include landing gear to facilitate takeoff, landing, and taxi. The landing gear of some aircraft includes a shock absorber that is pivotally connected to a truck beam at a distal or lower end thereof. The truck beam typically includes two or more axles upon which tires are mounted. In this regard, the truck beam may include a forward axle positioned forward of the shock absorber and an aft axle positioned aft of the shock absorber. Wheels may be mounted on an axle in tandem pairs.
During landing in conventional airplanes, a truck tilt actuator may position tandem axle wheels in a toes up position or a toes down position. The toes up position is a configuration in which the forward wheels on the main landing gear are at a higher position than that of the rear wheels on the main landing gear. A toes down position is a configuration in which the forward wheels are at a lower position than that of the rear wheels on the main landing gear. Upon landing, the force of touchdown causes the truck beam to rotate so that front and rear wheels are aligned substantially horizontally on the ground.
Air-ground detection systems determine when the landing gear wheel or wheels touch the ground during landing for spoiler deployment, brake activation, and/or other desirable functions. Conventional aircraft may utilize air-ground detection sensors which detect rotation of the truck beam and use this rotation to determine when landing gear wheels make contact with the ground.
However, this type of air-ground sensing system may not be usable with, or appropriate for, all types of landing gear. Accordingly, it would be advantageous to have a method and apparatus which takes into account one or more of the issues discussed above, as well as possibly other issues.